1. Field of the Invention
This invention relates to a reduced size fuel injector for use in internal combustion engines.
2. Disclosure Information
Electronic, or electromagnetically operated, fuel injectors have been used with internal combustion engines for many years. Such injectors typically employ fully-piloted needle valves which are generally elongate in shape and which seal by means of a tapered sealing surface which seats against a concentrically located mating surface situated within the valve body of the injector. This type of configuration is shown generally in U.S. Pat. No. 2,607,368 to Mayer, U.S. Pat. No. 2,616,955 to Dube et al., U.S. Pat. No. 2,637,344 to Matthews, U.S. Pat. No. 4,582,294 to Fargo and U.S. Pat. No. 4,705,324 to Kervagoret. All of these valves suffer from two types of deficiencies. First, the elongate structure of the valve necessitates that the complete injector be of considerable length, which can cause packaging problems if a valve is adapted for use as a fuel injector in certain types of engines. Second, the concentricity requirements of this type of structure demand special consideration during the manufacture of the valves and sometimes leaking, sticking, or other types of unsatisfactory operation result due to manufacturing errors.
U.S. Pat. No. 4,662,567 to Knapp discloses an electromagnetically operable fuel injector having a spherical valve closing member which is guided radially by not only the valve seat but also the valve stop. As alluded to above, such guide structures must be constructed with precision, and therefore, at considerable expense, if the resulting fuel injector must function without leaks at high speeds and feed pressures.
U.S. Pat. No. 4,715,396 to Fox discloses a proportional solenoid valve having a disc shape armature which acts directly upon a valve seat to control flow through the valve. This type of valve is generally not suitable for use as a compact fuel injector for an internal combustion engine because the width of the valve disc will prevent the injector from having a narrow profile.
Finally, U.S. Pat. No. 4,524,797 and U.S. Pat. No. 4,564,046, both to Lungo, disclose solenoid operated valves having permanent magnet armatures which are fully piloted and which have a normally open configuration. The fully piloted construction renders such valves subject to leaking resulting from any lack of parallelism between the sealing surfaces. Further, fuel injectors for engines, on the other hand, with the present fuel injector being no exception, generally employ a normally closed configuration.
It is an object of the present invention to provide an electronically operated fuel injector having a compact package volume.
It is another object of the present invention to provide an electronic fuel injector which is easily manufactured.
It is yet another object of the present invention to provide an electronic fuel injector which does not rely upon the concentricity of the valve group components in order to achieve a leakproof seal.
It is still another object of the present invention to provide an electronic fuel injector which has minimal length and diameter.
It is yet another object of the present invention to provide an electronic fuel injector having low operating friction characteristics, so as to provide superior time response.
Other objects, features, and advantages of the present invention will become apparent to the reader of this specification.